They fish together. They’ve done synchronized movements, though I can’t say I’ve seen the full-blown courtship behaviors portrayed in online videos.

But it does raise the tantalizing prospect loons might nest on the lake for the first time in at least a near-decade.

I’ve been up north for what will be nine years in December. In that time, we’ve not seen loons with young on Six Mile Lake.

It was not always so. My parents, who first started building on this home in 1999 and moved up permanently in 2005, regularly reported loons on the lake toting chicks on their backs.

A striking male ring-necked duck took advantage of the high water levels on Six Mile Lake to take a break and preen on the mostly submerged dock. Heavy rains had several docks on the lake under water much of this week.

It’s not clear why that ended, though Bill Scullon, the Michigan Department of Natural Resources field operations manager for the Upper Peninsula, offered some possible explanations.

Loons tend to return to sites where they’ve successfully nested before, so he thought it likely something might have happened to one or both of that original pair.

“There’s a lot of mortality with loons,” Scullon said.

Botulism, a paralyzing soil bacterium waterbirds can pick up by foraging, is a major threat and can kill thousands of loons in outbreak years, he said.

One form of botulism, type E, is primarily found in the Great Lakes region where common loons will stage during fall migration, according to the U.S. Geological Survey’s ScienceBase catalog. Several studies have been done to look at loon distribution, foraging patterns, how botulism toxins spread through the food chain and other potential transmission factors, to see if botulism can be controlled or whether the next outbreaks can be predicted, according to the website.

One possible vector for the toxin, according to reports, is loons feeding on round gobies, an invasive Eurasian fish thought to have been introduced to the Great Lakes in the early 1990s by ships dumping ballast water from the Black Sea. The bottom-dwelling gobies have become a key prey species for the loons.

Another report states the botulism die-offs events “have become more common and widespread” and often seem to coincide with years of warmer lake temperatures and lower water levels.

Other notable hazards for loons include avian influenza, commercial fishing — they can get caught up in nets — and if the birds wind up having to land on the ground, Scullon said.

Loon legs are set way back, a trait that makes them amazing divers and swimmers in water. The trade-off, however, is they can’t walk and must have an expanse of water to build up enough speed to take off.

Those forced down by weather or perhaps mistaking a rain-covered parking lot for water will be unable to get back in the air and can only push themselves along on their bellies to try to reach a suitable water body. Scullon said it’s unknown how many loons perish unseen after being grounded.

The inability to move well on land can make loons more vulnerable to predators as well, he said.

But loons that avoid such problems can live a long time — a former pair that became well-known at the Seney National Wildlife Refuge in Schoolcraft County are thought to be 37 and the female at least 38 years old, the oldest documented common loons in the world.

Yet if that initial pair perhaps was lost, why hasn’t another taken their place breeding at Six Mile Lake? The lake regularly has loons each spring, summer and fall, so they’re around, just not choosing to nest.

It could be a combination of reasons, Scullon said. Loons nest on floating vegetation or in shallow areas in quiet back bays. Again, they can’t move easily on land, so need to be close enough to the water’s edge to quickly slide back in if threatened.

Six Mile Lake in recent years has seen a lot of activity on the water, so disturbance could be a factor. But loons are fairly used to boat traffic, so wouldn’t be too spooked unless someone came right up to the nest — then they might be inclined to abandon it, Scullon said.

But boating activity does carry one other hazard to loons trying to brood eggs: wakes from passing boats or other watercraft, especially high-powered types, can swamp their low-lying nests.

It’s why some lakes will have no-wake zones established during the nesting season, he said.

If we do have locally nesting loons, Six Mile Lake residents might want to power down for a few weeks or avoid coming close to areas where the birds have been repeatedly seen, Scullon said.

“Give them space; leave them alone,” he said.

These restrictions don’t have to last for long. While loons take about 26 to 29 days to incubate eggs, the chicks only stay in the nest about two days after hatching, according to the Cornell Lab of Ornithology’s All About Birds website, www.allaboutbirds.org.

This past week brought another challenge if the loons are trying to nest at Six Mile: heavy rains have lake levels up over our dock and the one set up at the boat launch. This, too, can inundate the nest.

Scullon had one other explanation for why Six Mile Lake regularly has loons but no chicks: The birds are nesting elsewhere close by but foraging on the larger lake. He knows from personal observation of multiple pairs raising young at the Groveland Mine ponds in the past.

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Loons notwithstanding, it appears to be a very good early nesting year, Scullon said. He noticed Canada geese already had goslings on Lake Antoine, and we had a pair come up on the lawn in the backyard Sunday that had at least five downy yet fairly well-grown offspring.

Songbird fledglings won’t be far behind at this rate.

The first fawns are being reported as well, the start of the annual wave that comes in May and early June. So another gentle reminder that it’s normal for does to leave their fawns bedded down and concealed for long periods of time in the first few weeks. A fawn discovered alone usually has not been abandoned and should be left where found in almost all circumstances.

Betsy Bloom can be reached at 906-774-2772, ext. 240, or bbloom@ironmountaindailynews.com.